Superheater element with trifurcate groups



A. P. J. HUET 2,608,390

SUPEIRHEATER ELEMENT WITH TRIFURCATE GROUPS Flled June 5 1947 4,18% m f/Zzei INVENTOR Brim Fb w HHH H! Aug. 26, 1952 Patented Aug. 26, 1952 SUPERHEATER ELEMENT WITH TRIFURCATE GROUPS Andi- Philippe J eanI-Iuet, Paris, France, assignor :to Combustion Engineering-Superheater, Inc., a corporation of Delaware Application June 3, 1947, Serial No; 752,225 1 v b t In France July 11, 1941 7 Section 1, Public Law 690, August 8, 1946 Patent expires July 11, 1961 13 Claims.

This invention relates to steam superheater elements for use in locomotive and other smoke tube boilers. It is concerned particularly with elements of the kind in which the steam, in traversing that portion of the element which lies in a smoke tube, flows only once in each direction and base plurality of relatively small pipes or tubes conveying steam in one direction with: a single return bend at the fire box end of the element effecting the required reversal in the direction of steam for return flow through a secondgroup of small pipes conveying the steam in the opposite direction.

It is anobject of the present invention to provide a steam superheater element of the kind referredto above in which the junction or union of the fire-box ends of the tubescomprisedin the group of small tubes conveying steam in one direction andtheir connection to the tube or tubes. conveying steam in the opposite direction shall be of such construction and so disposed in the smoke tube as to afford relatively little obstruction to smoke tube. i

The most vulnerable portion of a steam superhe'ater element is that at its fire box end, due of course. to the proximity of such portion to the furnace, and it is another object of the invention tof p'rfovid a multiple pipe element of the kind indicated above in which the construction shall bejsuch that a relatively high steam speed may obtain in the fire box end portion of the element resultingin an elfective cooling thereof. A further object is to provide an element of improved construction in which the fire box end portion shallbe such that. its manufacture from heat resisting steel tubing Will be facilitated.

Some locomotive boilers have the fire box end portions of the smoke tubesaccommodating the superb-eater elements reduced in diameter and it is still another object of the present invention to provide a multiple pipe element'of the kind with which the invention is concerned in which the fire box end portion thereof may extend into the contracted part or throat of the smoke tube without so. reducing the cross-sectional area of that part of the smoke tube available for the the flow; of gases through the this invention the fire box ends of the severe 1 tubes conveying steam in one direction are united at a point spaced from the return bend of the element and are connected with the tubes cone veying steam in the opposite direction by a single conduit. Such conduit may include the said re: turn bend and the element thus have a fire box end portion comprising only two tubes.

According to the invention the joining of the two bundles of admission and return tubes is;

carried out with the aid of a single tube length joined by forging or welding on the one hand to the bundle of admission tubes, on the other hand to the return flow tubes. The said single tube can be straight and disposed on the axisof the steam tube or it can be bent and in this case the twopoints of junction of the tube with the two bundles can be placed non-symmetrically in the smoke tube in such fashion as to insure at the interior of the latter a judicious distribution of the different branches of the bundles whose tubes are preferably formed with offsetting bends and disposed so as not to oppose the passage of gas and on the other hand in such fashion as to permit direct access of the gas to the central part v of the smoke tube.

hottest gas.

increase and'decrease in size.

The invention will be best' understood upon consideration of the following detailed 'description of illustrative embodiments thereof when, read in conjunction with the accompanying I drawings in which:

Figure 1 is a fragmentary sectional view "of. a boiler flueshowing mounted thereinthe fir'} box end of asuperheater' unit embodyingthe' present invention;

Figure 2 is a similar angles to Figure 1;

Figures 3 and 4 are transverse sectional views along the correspondingly designated lines in Figure 1;

Figures 5 to 8 are views corresponding respectively to Figures 1 to 4 but showing another constructionalembodiment of the superheaterl.

unit in accordance with the invention.

view as seen at right aeoaseo I Referring to Figures 1 and 2 it will be seen that the superheater element located in the smoke tube a is made up of a bundle of three tubes 11, c, and d which are traversed by the steam admitted to the element and flowing in the direction of the arrows. The tube a is mounted in the usual manner in a tube sheet at the fire box end of the boiler. The bundle of return flow tubes likewise consists of three tubes g, h, which are traversed by the superheated steam flowing in the direction of the arrows. tubes 1), c and d and the return flow tubes 1, g, and h Within the interior of the smoke tube a is shown in Figure 3. It may be seen that the return flow tubes g, and h, are located centrally of or at the interior of the bundle of'admission tubes b, c, d, so as to be protected by the latter which in effect form a heat shield.

According to the invention the connection of the two tube bundles atthe smoke box end is carried out through the aid of a si-n'gletube z. Thist'ub'e is disposed in the case shown in Figures l and 2 along the axis of the flue. It is joined by means of a breeches piece 7' with the three-"return flow tubes f, g, and h and by a breechespie'ce k with the admission tubes 1), c, d. This tubular connection 1' may be created as an extension of the rounded breeches piece :1 producedby forge welding the tubes f, g, h, together with-the tube'ji projecting centrally from the group of tubes i, =9 and h. In effect the breeches k is formed by simultaneously forge welding the four tubes 'b', 6 d and 2' together, the tube 1' which is f larger diameter being located centrally within the tube bundle b, -'c and d which are distributed uniformly around the tube 2' (Fig. 4).

The method of joining tubes by forge welding steps is now well known and need not be described in detail herein, itbeing suflicient to state that, in such a process the end portions of two or more 'tubesto be joined, after being brought to welding heat, are placed in a female "die and a male 'd'i e or punch is introduced into the tube ends which splits and turns "outwardly the appropriateportions of the opposed walls of adjacent tubes and after bringing such portions intg -ablittin'g relation welds them together to form a common or union portion, sometimes wnasa bme hes piec he ope nd ofthi breeches-piece may be rounded and: joined to another tubegor it may be arched over and closed by a swagingoperation to form a return bendof a sup heater or li e, e eme t- T h Zyjc and dare preferably formed with en near their extremities as'may be seen at em Figures 1 and so as to permit their ends to be brought closer together to facilitate the forging of the breeches piece This bending extends [far enough along the tubes so as not to produce anabrupt obstruction of the smoke tubes.

andto leave sufiicient gas flow within the tube.

.In the preferred embodiment. shown in Figures fi and 'BJafseparate tube n interconnecting the ftWQTtubejbundles is bent 180 intermediate its ends at Z "and the two breeches .pieces k and .7 are then welded thereo at s. As shown the breech-es pieces and 7c are disposed nornsymmetrically within the flue a, the breeches-piece 7' belip'g locatedpn the axis of the flue while the breeches-piece 'k'is ofiset towards theupper part of the tube (Fig.

Inthis case also the bends e in the tubes "b, c anddof-theadmission bundle extend far enough alongtheir length so that in the region where these tubes are drawn together there will not be an obstruction ofiered to the flow of the gas. The tubes of the two bundles being located within the flue as seen in Figure '1 are held in position by suitable spacers and supports not illustrated.

The cross-section of the tube 2' or n located in the zone of highest temperature in the flue a may The relative disposition of the admission be smaller than the sum of the sections of the tubes 1), c and d of the admission bundle or of the aggregate cross section of the return flow tubes, insuch manner as to increase the speed of flow of steam within the junction tube 11. which will then be more efiectively cooled.

What I claim is:

l. A 'multi-tube superheater element comprising; a plurality of superheated steam or return flow tubes disposed in closely spaced and symmetrical relation about a longitudinal axis centrally located among them; a breeches piece joining said tubes together atone end thereof; a plurality of saturated steam or admission't'ubes disposed around said return flow tubes; a breeches piece integrally joining said admission tubes at" one end thereof; individual open' ended tubular portions forming parts of said breeches piece; and a junction tube interconnecting the open ends of said tubular portions of said two breeches pieces for connecting the group of admission tubes in series with the group of return flow tubes.

2. A superheater element as recited in claim I wherein said junction tube is an integral part of one of said breeches pieces.

-3. A superheater elementas recited'inclaim 1 wherein said junction tube is initially a separate tube having its two ends connected to the respec--- tive breeches piece. I

'4. A superheater element as recited in claim 1 wherein said breeches piece is initially a sepa rate U'-shaped tube having its ends connected to I said breeches pieces.

5. A multi-tube superheater element comprise ing; a plurality of superheated steam admission tubes joined together at one end by an integrals,

formed open ended breeches piece; a plurality of superheated steam return flow tubesalso in tegrally joined together at one end by 'a seco'nd' open ended forge welded breeches pie'c'etspaced' longitudinally from the breeches piece joining said admission tubes anda junction tubehavin'g; a U-bend "formed therein intermediate fits ends: with the latter connected to said openen'dsrbf two breeches pieces.

6. A superheater element as recited in claim-5 wherein the return flow tubes are grouped centrallyof the element with the admission tubes" disposed around and-outwardly of the latter.

'7. A superheater element as recited in 'claim'fi wherein the return flow tubes are disposed in" symmetrical arrangement close to and around a longitudinal axis located centrally among them. 8. A superheater element as .recited'inclaim 6. wherein the breeches piece joining the return" flow tubes is disposed on a longitudinal axis l'oe cated centrally with respect to said return.'flow" tubes and the breeches piece joining thej'admis sion tubes is disposed eccentrically'with respect I to said axis.

said return flow tubes. l

10. The method of manufacturing a metallic. multi-tube superheater unit comprising; disposing a plurality of return flow tubes symmetrically about an axis parallel to their length and forge welding them together at one end to form a breeches piece; disposing a plurality of admission tubes around said group of return flow tubes and forge welding them together to form a second breeches piece; and joining the two breeches pieces together to connect the group of admission tubes in series with the group of return flow tubes.

11. The method of manufacturing a metallic multi-tube superheater unit comprising; disposing a plurality of return flow tubes symmetrically about an axis parallel to their length and forge welding them together at one end to form an open ended breeches piece; disposing a plurality of admission tubes symmetrically around said group of return flow tubes and forge welding them together to form a second open ended breeches piece; and joining the open ends of the two breeches pieces together by an intermediate relatively short tube to connect the group of admission tubes in series with the group of return flow tubes.

12. The method of manufacturing a metallic multi-tube superheater unit comprising; disposing a group of return flow tubes symmetrically about an axis parallel to their length and forge welding them together at one end to form an open ended breeches piece; disposing a group of admission tubes symmetrically around said group of return flow tubes and forge welding them together to provide a second open ended breeches piece forming the open end of said second breeches piece eccentrically with respect to the group of tubes and disposing it eccentrically with respect to the open end of the breeches piece for the group of return flow tubes; forming a returnbend loop in a relatively short tube; and joining 6 the open ends of said two breeches pieces to the ends of said relatively short tube with the two breeches pieces offset transversely of the unit 7 for connecting the group of admission tubes in series with the group of return flow tubes.

13. The method of manufacturing a metallic multi-tube superheater unit comprising; disposing a group of return flow tubes symmetrically about an axis parallel to their length and forge welding them together at one end to form an open ended breeches piece; disposing a group of admission tubes symmetrically around said group of return flow tubes and forge welding them together to provide a second open ended breeches piece having its open end formed eccentrically with respect to the group of tubes and also disposed eccentrically with respect to the open end of the breeches piece for the group of return flow tubes; forming a return-bend loop in a relatively short tube; and joining the open ends of said two breeches pieces to the ends of said relatively short tube with the two breeches pieces offset transversely of the unit for connecting the group of admission tubes in series with the group of return flow tubes.

ANDRE PHILIPPE JEAN HUET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,184,986 Oatley et a1 May 30, 1916 1,352,535 Ryder Sept. 14, 1920 1,373,465 True Apr. 5, 1921 2,240,372 Huet Apr. 29, 1941 2,517,489 Huet Aug. 1, 1950 

